Touch Sensor with Edge-Balanced Macro-Feature Design

ABSTRACT

In one embodiment, a touch position-sensing panel comprising a sensing area comprising a substrate, a plurality of first electrodes in a first layer, the plurality of first electrodes comprising conductive mesh and arranged in a first direction, the first layer having a first plurality of gaps formed therein, a plurality of second electrodes in a second layer, the plurality of second electrodes comprising conductive mesh and arranged in a second direction generally perpendicular to the first direction, the second layer having a second plurality of gaps formed therein, and a plurality of capacitive nodes formed by the capacitive coupling of the plurality of first electrodes in the first layer and the plurality of second electrodes in a second layer, the plurality of capacity nodes comprising at least one center node, at least one edge node, and at least one corner node, the at least one center node, at least one edge node, and at least one corner node comprising approximately equal areas.

TECHNICAL FIELD

This disclosure generally relates to touch sensors.

BACKGROUND

A touch sensor may detect the presence and location of a touch or the proximity of an object (such as a user's finger or a stylus) within a touch-sensitive area of the touch sensor overlaid on a display screen, for example. In a touch sensitive display application, the touch sensor may enable a user to interact directly with what is displayed on the screen, rather than indirectly with a mouse or touch pad. A touch sensor may be attached to or provided as part of a desktop computer, laptop computer, tablet computer, personal digital assistant (PDA), smartphone, satellite navigation device, portable media player, portable game console, kiosk computer, point-of-sale device, or other suitable device. A control panel on a household or other appliance may include a touch sensor.

There are a number of different types of touch sensors, for example, resistive touch screens, surface acoustic wave touch screens, and capacitive touch screens. Herein, reference to a touch sensor may encompass a touch screen, and vice versa, where appropriate. When an object touches or comes within proximity of the surface of the capacitive touch screen, a change in capacitance may occur within the touch screen at the location of the touch or proximity. A touch-sensor controller may process the change in capacitance to determine its position on the touch screen.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a touch sensor and touch sensor controller in accordance with particular embodiments;

FIG. 2 illustrates a cross section of a touch sensor along the line 2-2 in accordance with particular embodiments;

FIGS. 3A, 3B, and 3C illustrate an arrangement of sense and drive electrodes in accordance with a conventional approach; and

FIGS. 4A, 4B, and 4C illustrate an arrangement of sense and drive electrodes in accordance with particular embodiments of the disclosure.

DESCRIPTION OF EXAMPLE EMBODIMENTS

FIG. 1 illustrates a touch sensor and touch sensor controller in accordance with particular embodiments. Touch sensor 10 and touch-sensor controller 12 may detect the presence and location of a touch or the proximity of an object within a touch-sensitive area of touch sensor 10. Herein, reference to a touch sensor may encompass both the touch sensor and its touch-sensor controller, where appropriate. Similarly, reference to a touch-sensor controller may encompass both the controller and its touch sensor, where appropriate. Touch sensor 10 may include one or more touch-sensitive areas, where appropriate. Touch sensor 10 may include an array of drive and sense electrodes (for example, electrodes 102 and 103 in FIGS. 2 through 4A, 4B, and 4C) or an array of electrodes of a single type disposed on one or more substrates, which may be made of a dielectric material. Herein, reference to a touch sensor may encompass both the electrodes of the touch sensor and the substrate(s) that they are disposed on, where appropriate. Alternatively, where appropriate, reference to a touch sensor may encompass the electrodes of the touch sensor, but not the substrate(s) that they are disposed on.

An electrode (whether a drive electrode or a sense electrode) may be an area of conductive material forming a shape, such as for example a disc, square, rectangle, quadrilateral, other suitable shape, or suitable combination of these shapes. One or more cuts in one or more layers of conductive material may (at least in part) create the shape of an electrode, and the area of the shape may (at least in part) be bounded by those cuts. In particular embodiments, the conductive material of an electrode may occupy approximately 100% of the area of its shape. As an example and not by way of limitation, an electrode may be made of indium tin oxide (ITO) and the ITO of the electrode may occupy approximately 100% of the area of its shape, where appropriate. In particular embodiments, the conductive material of an electrode may occupy substantially less than 100% (such as for example, approximately 5%) of the area of its shape. As an example and not by way of limitation, an electrode may be made of fine lines of metal or other conductive material (such as for example copper, silver, or a copper- or silver-based material) and the fine lines of conductive material may occupy substantially less than 100% (such as for example, approximately 5%) of the area of its shape in a hatched, mesh, or other suitable pattern. Although this disclosure describes or illustrates particular electrodes made of particular conductive material forming particular shapes with particular fills having particular patterns, this disclosure contemplates any suitable electrodes made of any suitable conductive material forming any suitable shapes with any suitable fills having any suitable patterns. Where appropriate, the shapes of the electrodes (or other elements) of a touch sensor may constitute in whole or in part one or more macro-features of the touch sensor. One or more macro-features of a touch sensor may determine one or more characteristics of its functionality. One or more characteristics of the implementation of those shapes (such as, for example, the conductive materials, fills, or patterns within the shapes) may constitute in whole or in part one or more micro-features of the touch sensor. One or more micro-features of the touch sensor may determine one or more optical features of the touch sensor, such as transmittance, refraction, or reflection.

A mechanical stack may contain the substrate (or multiple substrates) and the conductive material forming the drive or sense electrodes of touch sensor 10. As an example and not by way of limitation, the mechanical stack may include a first layer of optically clear adhesive (OCA) beneath a cover panel. The cover panel may be clear and made of a resilient material suitable for repeated touching, such as for example glass, polycarbonate, or poly(methyl methacrylate) (PMMA). This disclosure contemplates any suitable cover panel made of any suitable material. The first layer of optically clear adhesive may be disposed between the cover panel and the substrate with the conductive material forming the drive or sense electrodes. The mechanical stack may also include a second layer of optically clear adhesive and a dielectric layer (which may be made of PET or another suitable material, similar to the substrate with the conductive material forming the drive or sense electrodes). As an alternative, where appropriate, a thin coating of a dielectric material may be applied instead of the second layer of optically clear adhesive and the dielectric layer. The second layer of optically clear adhesive may be disposed between the substrate with the conductive material making up the drive or sense electrodes and the dielectric layer, and the dielectric layer may be disposed between the second layer of optically clear adhesive and an air gap to a display of a device including touch sensor 10 and touch-sensor controller 12. As an example only and not by way of limitation, the cover panel may have a thickness of approximately 1 mm; the first layer of optically clear adhesive may have a thickness of approximately 0.05 mm; the substrate with the conductive material forming the drive or sense electrodes may have a thickness of approximately 0.05 mm; the second layer of optically clear adhesive may have a thickness of approximately 0.05 mm; and the dielectric layer may have a thickness of approximately 0.05 mm. Although this disclosure describes a particular mechanical stack with a particular number of particular layers made of particular materials and having particular thicknesses, this disclosure contemplates any suitable mechanical stack with any suitable number of any suitable layers made of any suitable materials and having any suitable thicknesses. As an example and not by way of limitation, in particular embodiments, a layer of adhesive or dielectric may replace the dielectric layer, second layer of optically clear adhesive, and air gap described above, with there being no air gap to the display.

One or more portions of the substrate of touch sensor 10 may be made of polyethylene terephthalate (PET) or another suitable material. This disclosure contemplates any suitable substrate with any suitable portions made of any suitable material. In particular embodiments, the drive or sense electrodes in touch sensor 10 may be made of ITO in whole or in part. In particular embodiments, the drive or sense electrodes in touch sensor 10 may be made of fine lines of metal or other conductive material. As an example and not by way of limitation, one or more portions of the conductive material may be copper or copper-based and have a thickness of approximately 5 μm or less and a width of approximately 10 μm or less. As another example, one or more portions of the conductive material may be silver or silver-based and similarly have a thickness of approximately 5 μm or less and a width of approximately 10 μm or less. This disclosure contemplates any suitable electrodes made of any suitable material.

Touch sensor 10 may implement a capacitive form of touch sensing. In a mutual-capacitance implementation, touch sensor 10 may include an array of drive and sense electrodes forming an array of capacitive nodes. A drive electrode and a sense electrode may form a capacitive node. The drive and sense electrodes forming the capacitive node may come near each other, but not make electrical contact with each other. Instead, the drive and sense electrodes may be capacitively coupled to each other across a space between them. A pulsed or alternating voltage applied to the drive electrode (by touch-sensor controller 12) may induce a charge on the sense electrode, and the amount of charge induced may be susceptible to external influence (such as a touch or the proximity of an object). When an object touches or comes within proximity of the capacitive node, a change in capacitance may occur at the capacitive node and touch-sensor controller 12 may measure the change in capacitance. By measuring changes in capacitance throughout the array, touch-sensor controller 12 may determine the position of the touch or proximity within the touch-sensitive area(s) of touch sensor 10.

In a self-capacitance implementation, touch sensor 10 may include an array of electrodes of a single type that may each form a capacitive node. When an object touches or comes within proximity of the capacitive node, a change in self-capacitance may occur at the capacitive node and touch-sensor controller 12 may measure the change in capacitance, for example, as a change in the amount of charge needed to raise the voltage at the capacitive node by a pre-determined amount. As with a mutual-capacitance implementation, by measuring changes in capacitance throughout the array, touch-sensor controller 12 may determine the position of the touch or proximity within the touch-sensitive area(s) of touch sensor 10. This disclosure contemplates any suitable form of capacitive touch sensing, where appropriate.

In particular embodiments, one or more drive electrodes may together form a drive line running horizontally or vertically or in any suitable orientation. Similarly, one or more sense electrodes may together form a sense line running horizontally or vertically or in any suitable orientation. In particular embodiments, drive lines may run substantially perpendicular to sense lines. Herein, reference to a drive line may encompass one or more drive electrodes making up the drive line, and vice versa, where appropriate. Similarly, reference to a sense line may encompass one or more sense electrodes making up the sense line, and vice versa, where appropriate.

Touch sensor 10 may have drive and sense electrodes disposed in a pattern on one side of a single substrate. In such a configuration, a pair of drive and sense electrodes capacitively coupled to each other across a space between them may form a capacitive node. For a self-capacitance implementation, electrodes of only a single type may be disposed in a pattern on a single substrate. In addition or as an alternative to having drive and sense electrodes disposed in a pattern on one side of a single substrate, touch sensor 10 may have drive electrodes disposed in a pattern on one side of a substrate and sense electrodes disposed in a pattern on another side of the substrate. Moreover, touch sensor 10 may have drive electrodes disposed in a pattern on one side of one substrate and sense electrodes disposed in a pattern on one side of another substrate. In such configurations, an intersection of a drive electrode and a sense electrode may form a capacitive node. Such an intersection may be a location where the drive electrode and the sense electrode “cross” or come nearest each other in their respective planes. The drive and sense electrodes do not make electrical contact with each other—instead they are capacitively coupled to each other across a dielectric at the intersection. Although this disclosure describes particular configurations of particular electrodes forming particular nodes, this disclosure contemplates any suitable configuration of any suitable electrodes forming any suitable nodes. Moreover, this disclosure contemplates any suitable electrodes disposed on any suitable number of any suitable substrates in any suitable patterns.

As described above, a change in capacitance at a capacitive node of touch sensor 10 may indicate a touch or proximity input at the position of the capacitive node. Touch-sensor controller 12 may detect and process the change in capacitance to determine the presence and location of the touch or proximity input. Touch-sensor controller 12 may then communicate information about the touch or proximity input to one or more other components (such one or more central processing units (CPUs) or digital signal processors (DSPs)) of a device that includes touch sensor 10 and touch-sensor controller 12, which may respond to the touch or proximity input by initiating a function of the device (or an application running on the device) associated with it. Although this disclosure describes a particular touch-sensor controller having particular functionality with respect to a particular device and a particular touch sensor, this disclosure contemplates any suitable touch-sensor controller having any suitable functionality with respect to any suitable device and any suitable touch sensor.

Touch-sensor controller 12 may be one or more integrated circuits (ICs) —such as for example general-purpose microprocessors, microcontrollers, programmable logic devices or arrays, application-specific ICs (ASICs). In particular embodiments, touch-sensor controller 12 comprises analog circuitry, digital logic, and digital non-volatile memory. In particular embodiments, touch-sensor controller 12 is disposed on a flexible printed circuit (FPC) bonded to the substrate of touch sensor 10, as described below. In particular embodiments, multiple touch-sensor controllers 12 are disposed on the FPC. In some embodiments, the FPC may have no touch-sensor controllers 12 disposed on it. The FPC may couple touch sensor 10 to a touch-sensor controller 12 located elsewhere, such as for example, on a printed circuit board of the device. Touch-sensor controller 12 may include a processor unit, a drive unit, a sense unit, and a storage unit. The drive unit may supply drive signals to the drive electrodes of touch sensor 10. The sense unit may sense charge at the capacitive nodes of touch sensor 10 and provide measurement signals to the processor unit representing capacitances at the capacitive nodes. The processor unit may control the supply of drive signals to the drive electrodes by the drive unit and process measurement signals from the sense unit to detect and process the presence and location of a touch or proximity input within the touch-sensitive area(s) of touch sensor 10. The processor unit may also track changes in the position of a touch or proximity input within the touch-sensitive area(s) of touch sensor 10. The storage unit may store programming for execution by the processor unit, including programming for controlling the drive unit to supply drive signals to the drive electrodes, programming for processing measurement signals from the sense unit, and other suitable programming, where appropriate. Although this disclosure describes a particular touch-sensor controller having a particular implementation with particular components, this disclosure contemplates any suitable touch-sensor controller having any suitable implementation with any suitable components.

Tracks 14 of conductive material disposed on the substrate of touch sensor 10 may couple the drive or sense electrodes of touch sensor 10 to connection pads 16, also disposed on the substrate of touch sensor 10. As described below, connection pads 16 facilitate coupling of tracks 14 to touch-sensor controller 12. Tracks 14 may extend into or around (e.g. at the edges of) the touch-sensitive area(s) of touch sensor 10. Particular tracks 14 may provide drive connections for coupling touch-sensor controller 12 to drive electrodes of touch sensor 10, through which the drive unit of touch-sensor controller 12 may supply drive signals to the drive electrodes. Other tracks 14 may provide sense connections for coupling touch-sensor controller 12 to sense electrodes of touch sensor 10, through which the sense unit of touch-sensor controller 12 may sense charge at the capacitive nodes of touch sensor 10. Tracks 14 may be made of fine lines of metal or other conductive material. As an example and not by way of limitation, the conductive material of tracks 14 may be copper or copper-based and have a width of approximately 100 μm or less. As another example, the conductive material of tracks 14 may be silver or silver-based and have a width of approximately 100 μm or less. In particular embodiments, tracks 14 may be made of ITO in whole or in part in addition or as an alternative to fine lines of metal or other conductive material. Although this disclosure describes particular tracks made of particular materials with particular widths, this disclosure contemplates any suitable tracks made of any suitable materials with any suitable widths. In addition to tracks 14, touch sensor 10 may include one or more ground lines terminating at a ground connector (which may be a connection pad 16) at an edge of the substrate of touch sensor 10 (similar to tracks 14).

Connection pads 16 may be located along one or more edges of the substrate, outside the touch-sensitive area(s) of touch sensor 10. As described above, touch-sensor controller 12 may be on an FPC. Connection pads 16 may be made of the same material as tracks 14 and may be bonded to the FPC using an anisotropic conductive film (ACF). Connection 18 may include conductive lines on the FPC coupling touch-sensor controller 12 to connection pads 16, in turn coupling touch-sensor controller 12 to tracks 14 and to the drive or sense electrodes of touch sensor 10. In another embodiment, connection pads 16 may be connected to an electro-mechanical connector (such as a zero insertion force wire-to-board connector); in this embodiment, connection 18 may not need to include an FPC. This disclosure contemplates any suitable connection 18 between touch-sensor controller 12 and touch sensor 10.

In particular embodiments, touch sensor 10 may have a multi-layer configuration, with drive electrodes disposed in a pattern on one side of a substrate and sense electrodes disposed in a pattern on another side of the substrate. In such a configuration, a pair of drive and sense electrodes capacitively couple to each other at the intersection of a drive electrode and sense electrode. In particular embodiments, a multi-layer configuration of drive and sense electrodes may satisfy certain space and/or shape constraints with respect to the construction of touch sensor 10. Particular embodiments and examples of multi-layer configurations of drive and sense electrodes will be discussed further with respect to FIGS. 2 through 4A, 4B, and 4C.

FIG. 2 illustrates a cross section of touch sensor 10 along lines 2-2 in accordance with particular embodiments. Touch sensor 10 comprises a mechanical stack 100 and a display 110. Mechanical stack 100, which overlays display 110, includes a substrate 101, a drive electrode 102, a plurality of sense electrodes 103, a plurality of gaps 104, an optically clear adhesive 105, and a cover panel 106.

Substrate 101 has a plurality of surfaces, including a first surface 101 a facing display 110 and a second surface 101 b facing cover panel 106. Substrate 101 may be formed from a transparent, non-conductive material such as glass or a plastic as discussed in conjunction with FIG. 1. Drive electrode 102 is located on first surface 101 a of substrate 101, such that drive electrode 102 is located between substrate 101 and display 110. In various embodiments, there may be an air gap between drive electrode 102 and display 110. This cross sectional view provides a view of the length of one drive electrode, drive electrode 102. In a particular embodiment, a plurality of drive electrodes 102 may be located between substrate 101 and display 110, with lengths running generally parallel to drive electrode 102. Each of a plurality of drive electrodes 102 may be separated from one or more adjacent drive electrode by a cut in the conductive material, or a gap. A gap between adjacent drive electrodes may be as narrow as possible to reduce visibility of the cuts. In some embodiments, a gap between drive electrodes may have a width of approximately 10 μm to 5 μm, and in particular embodiments the width may be approximately 10 μm. Drive electrodes may be formed from any suitable material, including conductive mesh and ITO, as discussed in conjunction with FIG. 1.

Sense electrodes 103 are located on second surface 101 b of substrate 101, such that sense electrodes 103 are located between substrate 101 and cover panel 106. Each sense electrode 103 is separated from adjacent sense electrodes 103 by gaps 104. Gaps 104 are cuts in the lines of conductive material, such as copper, and may be as narrow as possible. In various embodiments, gaps 104 may have a width of approximately 10 μm to 5 μm, and in particular embodiments the width may be approximately 10 μm. This cross sectional view provides a view of the widths of sense electrodes 103. In certain embodiments, the widths of a touch sensor's sense electrodes may be shorter or longer than sense electrodes 103 as illustrated. In various embodiments, the widths of sense electrodes may be generally the same for all sense electrodes or may vary for each sense electrode 103. Further, in certain embodiments, there may be a greater or fewer number of sense electrodes that illustrated herein. Sense electrodes 103 may be formed from any suitable material, including conductive mesh and ITO, as discussed in conjunction with FIG. 1. Sense electrodes 103 may form patterns that are interpolated. For example, two adjacent sense electrodes 103 may form a pattern in which each electrode has side portions which cover the same stripe-shaped region of a panel, such as a sensing region. Each electrode may cover a portion of the stripe-shaped region, alternating coverage between one electrode and the other along a length of the side regions in an interleaved manner. In some examples, adjacent sense electrodes 103 have side portions that each cover approximately half of the side regions. In certain embodiments, any proportion of the side regions may be encompassed within the electrode.

Although, as illustrated, drive electrode 102 and sense electrodes 103 do not make electrical contact, they may capacitively couple to create capacitive nodes. Capacitive nodes may be identified based on their location within touch sensor 10. For example, a capacitive node located in a corner of touch sensor 10 may be identified as a corner node, a capacitive node located along an edge of touch sensor 10 may be identified as an edge node, and a capacitive node located away from edges and corners of touch sensor 10 may be identified as a center node.

Cover panel 106 is attached to sense electrodes 103 with optically clear adhesive 105. Cover panel 106 may be clear and made of a resilient material as discussed in conjunction with FIG. 1. As illustrated, light generated by display 110 passes through mechanical stack 100 and is visible to a user of touch sensor 10 through cover panel 106.

In certain embodiments, there may be additional components not illustrated herein. For example, adhesive may used between various layers within mechanical stack 100 or between mechanical stack 100 and display 110. Certain embodiments may include a second substrate and, in certain circumstances, sense electrodes may be attached to the first substrate and drive electrodes may be attached to the second substrate.

FIGS. 3A, 3B, and 3C illustrate an arrangement of sense and drive electrodes in accordance with a conventional approach. FIG. 3A illustrates a drive electrode layer 30 with a particular pattern of drive electrodes that could be used in touch sensor 10 as illustrated in FIG. 1. Drive electrode layer 30 includes drive electrodes 102 a, 102 b, 102 c, and 102 d.

Drive electrode 102 c comprises a center region 310, two side regions 312 and 314, two outer boundaries 316 and 318, a repeating shape element 320, and a plurality of rectangular arms 324. Side region 312 runs along one side of center region 310 and side region 314 runs along the opposite side of center region 310. Both run parallel to each other and center region 310.

Each side region 312 and 314 have rectangular arms 324 extending from center region 310 with a length L1. Length L1 is approximately equal to a width W1 of center region 310 of drive electrode 102 c. Each rectangular arm 324 is separated from an adjacent rectangular arm 324 in side regions 312 and 314, respectively, by a rectangular space. In this embodiment, a width W2 of each rectangular arm 324 is approximately the same as a width W3 of each rectangular space, such that approximately half of the total area of each side region 312 and 314 is encompassed within the area of drive electrode 102 c. Rectangular arms 324 are formed in an alternating fashion such that a rectangular arm in side region 312 is not in the same row as a rectangular arm is side region 314. In certain embodiments, rectangular arms 324 may be formed such that a rectangular arm in side region 312 is in the same row as a rectangular arm in side region 314. In particular embodiments, arms 324 may be rectangular, square, have curved edges, or may be of any suitable shape. In various embodiments, a rectangular arm may be referred to as a digit.

The shape of drive electrode 102 c is made up of a plurality of repeated shape elements 320. Each shape element 320 has one conductive rectangular arm 324 in each side region 312 and 314 and these rectangular arms 324 are linked by a section of center region 310. The ends of a single shape element 320 are illustrated by dashed lines in FIG. 3A. Each shape element 320 has a length L2, which is approximately equal to twice the width of a rectangular arm 324, or approximately twice width W2. The length L2 is the repeat length of the drive electrode pattern. Each shape element 320 has a width W4, which is approximately equal to the total width of center region 310 and both side regions 312 and 314, or approximately thrice length L1 or thrice width W1. Width W4 is approximately equal to the distance between edges 316 and 318 of drive electrode 102 c. In this embodiment, drive electrode 102 c includes seven repeating shape elements 320 in drive electrode layer 30. In certain embodiments, drive electrode 102 c may be formed by repeating shape elements 322, which are opposite handed compared to shape elements 320.

Drive electrodes 102 a and 102 b have shapes similar to drive electrode 102 c with similar dimensions. Drive electrode 102 d also has similar shapes and similar dimensions in its center region 310 and side region 312. Drive electrode 102 d is on the right hand side of drive electrode layer 30. Therefore, drive electrode 102 d does not have a side region 314 with rectangular arms. In various embodiments, drive electrodes located near edges of touch sensor 10 may only include one side region.

Rectangular arms 324 in side region 312 of drive electrode 102 c are interpolated with rectangular arms of drive electrode 102 b, such that space between rectangular arms 324 in side region 312 is generally filled by rectangular arms of drive electrode 102 b. Interpolated drive electrodes 102 b and 102 c are electrically isolated from each other by one of a plurality of gaps 104 a, where each gap 104 a is a cut in the lines of conductive material, such as copper, that comprise drive electrodes 102 a, 102 b, 102 c, and 102 d. Rectangular arms 324 in side region 314 of drive electrode 102 c are interpolated with rectangular arms of drive electrode 102 d, such that space between rectangular arms 324 in side region 314 is generally filled by rectangular arms of drive electrode 102 d. Interpolated drive electrodes 102 c and 102 d are electrically isolated from each by another gap 104 a. The patterns of side regions of adjacent drive electrodes may be complimentary in this way, such that the approximately 100% of the area of a side region may be encompassed within adjacent drive electrodes, excepting the area of gaps 104 a. In various embodiments, some or all drive electrodes in drive electrode layer 30 may be interpolated with one or more adjacent drive electrodes. In certain embodiments, touch sensor 10 may include any suitable number of drive electrodes for its shape and size.

FIG. 3B illustrates a sense electrode layer 35 with a particular pattern of sense electrodes that could be used in touch sensor 10 as illustrated in FIG. 1. Sense electrode layer 35 includes sense electrodes 103 a, 103 b, 103 c, and 103 d.

Sense electrode 103 c comprises a center region 311, two side regions 313 and 315, two outer boundaries 317 and 319, a repeating shape element 321, and a plurality of rectangular arms 325. Side region 313 runs along one side of center region 311 and side region 315 runs along the opposite side of center region 311. Both run parallel to each other and center region 311.

Each side region 313 and 315 have rectangular arms 325 extending from center region 311 with a length L3. Length L3 is approximately equal to a width W5 of center region 311 of sense electrode 103 c. In various embodiments, width W5 may be approximately equal to width W1 of center region 310 of drive electrode 102 c. Each rectangular arm 325 is separated from an adjacent rectangular arm 325 in side regions 313 and 315, respectively, by a rectangular space. In this embodiment, a width W6 of each rectangular arm 325 is approximately the same as a width W7 of each rectangular space, such that approximately half of the total area of each side region 313 and 315 is encompassed with the area of sense electrode 103 c. In various embodiments, width W6 may be approximately equal to width W2 of each rectangular arm 324 of drive electrode 102 c. Rectangular arms 325 are formed in an alternating fashion such that a rectangular arm in side region 313 is not in the same row as a rectangular arm is side region 315. In certain embodiments, rectangular arms 325 may be formed such that a rectangular arm in side region 313 is in the same row as a rectangular arm in side region 315. In particular embodiments, arms 325 may be rectangular, square, have curved edges, or may be of any suitable shape. In various embodiments, a rectangular arm may be referred to as a digit.

The shape of sense electrode 103 c is made up of a plurality of repeated shape elements 321. Each shape element 321 has one conductive rectangular arm 325 in each side region 313 and 315 and these rectangular arms 325 are linked by a section of center region 311. The ends of a single shape element 321 are illustrated by dashed lines in FIG. 3B. Each shape element 321 has a length L4, which is approximately equal to twice the width of a rectangular arm 325, or approximately twice width W6. The length L4 is the repeat length of the sense electrode pattern. Each shape element 321 has a width W8, which is approximately equal to the total width of center region 311 and both side regions 313 and 315, or approximately thrice length L3 or thrice width W5. Width W8 is approximately equal to the distance between edges 317 and 319 of sense electrode 103 c. In this embodiment, sense electrode 103 c includes seven repeating shape elements 321 in sense electrode layer 35. In certain embodiments, sense electrode 103 c may be formed by repeating shape elements 323, which are opposite handed compared to shape elements 321.

Sense electrodes 103 a and 103 b have shapes similar to sense electrode 103 c with similar dimensions. Sense electrode 103 d also has similar shapes and similar dimensions in its center region 311 and side region 313. Sense electrode 103 d is on the bottom side of sense electrode layer 35. Therefore, sense electrode 103 d does not have a side region 315 with rectangular arms. In various embodiments, sense electrodes located near edges of touch sensor 10 may only include one side region.

Rectangular arms 325 in side region 313 of sense electrode 103 c are interpolated with rectangular arms of sense electrode 103 b, such that space between rectangular arms 325 in side region 313 is generally filled by rectangular arms of sense electrode 103 b. Interpolated sense electrodes 103 b and 103 c are electrically isolated from each other by one of a plurality of gaps 104 a, where each gap 104 a is a cut in the lines of conductive material, such as copper, that comprise sense electrodes 103 a, 103 b, 103 c, and 103 d. Rectangular arms 325 in side region 315 of sense electrode 103 c are interpolated with rectangular arms of sense electrode 103 d, such that space between rectangular arms 325 in side region 315 is generally filled by rectangular arms of sense electrode 103 d. Interpolated sense electrodes 103 c and 103 d are electrically isolated from each by another gap 104 a. The patterns of side regions of adjacent sense electrodes may be complimentary in this way, such that the approximately 100% of the area of a side region may be encompassed within adjacent sense electrodes, excepting the area of gaps 104 a. In various embodiments, some or all sense electrodes in sense electrode layer 35 may be interpolated with one or more adjacent sense electrodes. In certain embodiments, touch sensor 10 may include any number of sense electrodes suitable for its shape and size.

FIG. 3C illustrates a pattern created by overlaying drive electrode layer 30 with sense electrode layer 35 in touch sensor 10 as illustrated in FIG. 1. Overlaying drive electrodes 102 a, 102 b, 102 c, and 102 d with sense electrodes 103 a, 103 b, 103 c, and 103 d creates one or more capacitive nodes, for example, capacitive nodes 140 a, 140 b, and 140 c.

Drive electrodes, as illustrated in FIG. 3A, generally run in one direction and are coupled to surface 101 a of substrate 101 described in conjunction with FIGS. 1 and 2. Sense electrodes, as illustrated in FIG. 3B, generally run in a direction orthogonal to the drive electrodes and are coupled to side 101 b of substrate 101 as described in conjunction with FIGS. 1 and 2. In various embodiments, the drive and sense electrodes can be aligned based on the different shape elements 320 and 321. In the embodiment illustrated in FIG. 3 c, drive electrodes and sense electrodes are arranged such that respective side edges 316 and 318 of drive electrode 102 a, 102 b, 102 c, and 102 d, are aligned with the ends of shape elements 321 of sense electrode 103 a, 103 b, 103 c, and 103 d and respective side edges 317 and 319 of sense electrodes 103 a, 103 b, 103 c, and 103 d are aligned with the ends of shape elements 320 of drive electrodes 102 a, 102 b, 102 c, and 102 d. Although drive electrodes and sense electrodes do not make electrical contact, they are able to capacitively couple to form capacitive nodes at the points where a drive electrode intersects or overlays a sense electrode.

Capacitive node 140 a is created when drive electrode 102 d is overlaid with sense electrode 103 c. Capacitive node 140 a is shaded a light grey and has an area of approximately 12 units, where each unit has an area of width W2 by width W6. Because capacitive node 140 a is located near the right hand edge of touch sensor 10, it may be referred to as an edge node in various embodiments. In certain embodiments, along its edges touch sensor 10 may have any number of edge nodes suitable for its shape and size.

Capacitive node 140 b is created when drive electrode 102 d is overlaid with sense electrode 103 d. Capacitive node 140 b is shaded a darker grey and has an area of approximately 9 units, where each unit has an area of width W2 by width W6. Because capacitive node 140 b is located near the bottom, right corner of touch sensor 10, it may be referred to as a corner node in various embodiments. In embodiments where touch sensor 10 has a generally rectangular shape, touch sensor 10 will have four corner nodes. In certain embodiments, touch sensor 10 may have any number of corner nodes suitable for its shape and size.

Capacitive node 140 c is created when drive electrode 102 c is overlaid with sense electrode 103 c. Capacitive node 140 c is shaded darkest grey and has an area of approximately 16 units, where each unit has an area of width W2 by width W6. Because capacitive node 140 c is located away from edges and corners of touch sensor 10, it may be referred to as a center node in various embodiments. In various embodiments, nodes in touch sensor 10 located away from edges and corners will each be center nodes. In certain embodiments, touch sensor 10 may have any number of center nodes suitable for its shape and size.

In this conventional layout, capacitive node 140 a, the edge node, has an area smaller than capacitive node 140 c; capacitive node 140 a is approximately 75% of the area of capacitive node 140 c. Capacitive node 140 b, the corner node, has an area smaller than capacitive nodes 140 a and 140 c; capacitive node 140 b is approximately 56.25% of the area of capacitive node 140 c. Conventional techniques may focus on edge performance in linearity and accuracy, and this layout may provide marginally improved linearity and accuracy in performance at the edge of touch sensor 10. Thus, when a user touches at the edge of touch screen 10, he or she may experience a marginally better reporting position. However, contrary to the conventional wisdom, the teachings of the disclosure recognize that this marginal improvement may be traded off for superior total performance of touch screen 10 by ensuring approximately equal areas for each capacitive node, including nodes of each node type: edge nodes, corner nodes, and center nodes. In various embodiments, touch screen controller 12 may require that all nodes have the same unit area to address noise effectively. Additional benefits may arise from modifying the unit areas of each node including improved uniformity in sensitivity and increase signaling capabilities by edge and corner nodes.

FIGS. 4A, 4B, and 4C illustrate an arrangement of drive electrodes 102 and sense electrodes 103 in accordance with particular embodiments of the disclosure. FIG. 4A illustrates a drive electrode layer 40 with a particular pattern of drive electrodes that could be used in touch sensor 10 as illustrated in FIG. 1. Drive electrode layer 40 includes drive electrodes 102 f, 102 g, 102 h, and 102 i.

Drive electrode 102 h comprises a center region 410, two side regions 412 and 414, two outer boundaries 416 and 418, a repeating shape element 420, and a plurality of rectangular arms 424. Side region 412 runs along one side of center region 410 and side region 414 runs along the opposite side of center region 410. Both run parallel to each other and center region 410.

Each side region 412 and 414 have rectangular arms 424 extending from center region 410 with a length L11. Length L11 is approximately equal to a width W11 of center region 410 of drive electrode 102 h. Each rectangular arm 424 is separated from an adjacent rectangular arm 424 in side regions 412 and 414, respectively, by a rectangular space. In this embodiment, a width W12 of each rectangular arm 424 is approximately the same as a width W13 of each rectangular space, such that approximately half of the total area of each side region 412 and 414 is encompassed within the area of drive electrode 102 h. Rectangular arms 424 are formed in an alternating fashion such that a rectangular arm in side region 412 is not in the same row as a rectangular arm is side region 414. In certain embodiments, rectangular arms 424 may be formed such that a rectangular arm in side region 412 is in the same row as a rectangular arm in side region 414. In particular embodiments, arms 424 may be rectangular, square, have curved edges, or may be of any suitable shape. In various embodiments, a rectangular arm may be referred to as a digit.

The shape of drive electrode 102 h is made up of a plurality of repeated shape elements 420. Each shape element 420 has one conductive rectangular arm 424 in each side region 412 and 414 and these rectangular arms 424 are linked by a section of center region 410. The ends of a single shape element 420 are illustrated by dashed lines in FIG. 4A. Each shape element 420 has a length L12, which is approximately equal to twice the width of a rectangular arm 424, or approximately twice width W12. The length L12 is the repeat length of the drive electrode pattern. Each shape element 420 has a width W14, which is approximately equal to the total width of center region 410 and both side regions 412 and 414, or approximately thrice length L11 or thrice width W11. Width W14 is approximately equal to the distance between edges 416 and 418 of drive electrode 102 h. In this embodiment, drive electrode 102 h includes eight repeating shape elements 420. In certain embodiments, drive electrode 102 h may be formed by repeating shape elements 422, which are opposite handed compared to shape elements 420. Drive electrode 102 g includes shapes similar to drive electrode 102 h with similar dimensions.

Drive electrode 102 i is on the right hand side drive electrode layer 40. Drive electrode 102 i also has similar shapes and similar dimensions to drive electrodes 102 g and 102 h in side region 412. Drive electrode 102 i has a center region 410 with a width W19; W11 of center regions 410 of drive electrodes 102 g and 102 h is approximately two-thirds of W19. Drive electrode 102 i does not have a side region 314 with rectangular arms. Drive electrode 102 f includes shapes similar to drive electrode 102 i with an opposite handed orientation. Drive electrode 102 f is on the left hand side of drive layer 40. Drive electrode 102 f has similar shapes and similar dimensions to drive electrodes 102 g and 102 h in side region 414. Drive electrode 102 f does not have side region 412. Similar to drive electrode 102 i, drive electrode 102 f has a center region 410 with a width W19. In certain embodiments, drive electrodes located near edges of touch sensor 10 may have any suitable center region width to ensure edge and corner capacitive nodes have approximately equal areas to center nodes. In various embodiments, drive electrodes located near edges of touch sensor 10 may only include one side region and may have any suitable dimensions to allow for edge nodes, corner nodes, and center nodes with approximately areas.

Rectangular arms 424 in side region 412 of drive electrode 102 h are interpolated with rectangular arms of drive electrode 102 g, such that space between rectangular arms 424 in side region 412 is generally filled by rectangular arms of drive electrode 102 g. Interpolated drive electrodes 102 g and 102 h are electrically isolated from each other by one of a plurality of gaps 104 a, where each gap 104 a is a cut in the lines of conductive material, such as copper, that comprise drive electrodes 102 f, 102 g, 102 h, and 102 i. Rectangular arms 424 in side region 414 of drive electrode 102 h are interpolated with rectangular arms of drive electrode 102 i, such that space between rectangular arms 424 in side region 414 is generally filled by rectangular arms of drive electrode 102 i. Interpolated drive electrodes 102 h and 102 i are electrically isolated from each by another gap 104 a. The patterns of side regions of adjacent drive electrodes may be complimentary in this way, such that the approximately 100% of the area of a side region may be encompassed within adjacent drive electrodes, excepting the area of gaps 104 a. In various embodiments, some or all drive electrodes in drive electrode layer 40 may be interpolated with one or more adjacent drive electrodes. In certain embodiments, touch sensor 10 may include any suitable number of drive electrodes for its shape and size. Drive electrodes in various embodiments may be any suitable length and width and the length and/or width of drive electrodes within a particular touch sensor may vary.

FIG. 4B illustrates a sense electrode layer 45 with a particular pattern of sense electrodes that could be used in touch sensor 10 as illustrated in FIG. 1. Sense electrode layer 45 includes sense electrodes 103 f, 103 g, 103 h, and 103 i.

Sense electrode 103 h comprises a center region 411, two side regions 413 and 415, two outer boundaries 417 and 419, a repeating shape element 421, and a plurality of rectangular arms 425. Side region 413 runs along one side of center region 411 and side region 415 runs along the opposite side of center region 411. Both run parallel to each other and center region 411.

Each side region 413 and 415 have rectangular arms 425 extending from center region 411 with a length L13. Length L13 is approximately equal to a width W15 of center region 411 of sense electrode 103 h. In various embodiments, W15 may be approximately equal to W11 of drive electrode 102 h. Each rectangular arm 425 is separated from an adjacent rectangular arm 425 in side regions 413 and 415, respectively, by a rectangular space. In this embodiment, a width W16 of each rectangular arm 425 is approximately the same as a width W17 of each rectangular space, such that approximately half of the total area of each side region 413 and 415 is encompassed within the area of sense electrode 103 h. In various embodiments, width W16 may be approximately equal to width W12 of each rectangular arm 424 of drive electrode 102 h. Rectangular arms 425 are formed in an alternating fashion such that a rectangular arm in side region 413 is not in the same row as a rectangular arm is side region 415. In certain embodiments, rectangular arms 425 may be formed such that a rectangular arm in side region 413 is in the same row as a rectangular arm in side region 415. In particular embodiments, arms 425 may be rectangular, square, have curved edges, or may be of any suitable shape. In various embodiments, a rectangular arm may be referred to as a digit.

The shape of sense electrode 103 h is made up of a plurality of repeated shape elements 421. Each shape element 421 has one conductive rectangular arm 425 in each side region 413 and 415 and these rectangular arms 425 are linked by a section of center region 411. The ends of a single shape element 421 are illustrated by dashed lines in FIG. 4B. Each shape element 421 has a length L14, which is approximately equal to twice the width of a rectangular arm 425, or approximately twice width W16. The length L14 is the repeat length of the sense electrode pattern. Each shape element 421 has a width W18, which is approximately equal to the total width of center region 411 and both side regions 413 and 415, or approximately thrice length L13 or thrice width W15. Width W18 is approximately equal to the distance between edges 417 and 419 of sense electrode 103 h. In this embodiment, sense electrode 103 h includes eight repeating shape elements 421 in sense electrode layer 45. In certain embodiments, sense electrode 103 h may be formed by repeating shape elements 423, which are opposite handed compared to shape elements 421. Sense electrode 103 g includes shapes similar to sense electrode 103 h with similar dimensions. Sense electrode 103 i is on the bottom side of sense layer 45. Sense electrode 103 i also has similar shapes and similar dimensions to sense electrodes 103 g and 103 h in side region 413. Sense electrode 103 i has a center region 411 with a width W20; W18 of sense electrodes 103 g and 103 h is approximately two-thirds of width W18. In various embodiments, width W20 is approximately equal to W19 of drive electrode 102 i. Sense electrode 103 i does not have a side region 413 with rectangular arms. Sense electrode 103 f includes shapes similar to sense electrode 103 i with an opposite handed orientation. Sense electrode 103 f is on the top side of sense electrode layer 45. Sense electrode 103 f has similar shapes and similar dimensions to sense electrodes 103 g and 103 h in side region 413. Sense electrode 103 f does not have a side region 415. Similar to sense electrode 103 i, sense electrode 103 f has a center region 411 with a width W20. In certain embodiments, sense electrodes located near edges of touch sensor 10 may have any suitable center region width to ensure edge and corner capacitive nodes have approximately equal areas to center nodes. Sense electrode 102 i does not have a side region 315 with rectangular arms. In various embodiments, drive electrodes located near edges of touch sensor 10 may only include one side region and may have any suitable dimensions to allow for edge nodes, corner nodes, and center nodes with approximately areas.

Rectangular arms 425 in side region 413 of sense electrode 103 h are interpolated with rectangular arms of sense electrode 103 g, such that space between rectangular arms 425 in side region 413 is generally filled by rectangular arms of sense electrode 103 g. Interpolated sense electrodes 103 g and 103 h are electrically isolated from each other by one of a plurality of gaps 104 a, where each gap 104 a is a cut in the lines of conductive material, such as copper, that comprise sense electrodes 103 f, 103 g, 103 h, and 103 i. Rectangular arms 425 in side region 415 of sense electrode 103 h are interpolated with rectangular arms of sense electrode 103 i, such that space between rectangular arms 425 in side region 415 is generally filled by rectangular arms of sense electrode 103 i. Interpolated sense electrodes 103 h and 103 i are electrically isolated from each by another gap 104 a. The patterns of side regions of adjacent sense electrodes may be complimentary in this way, such that the approximately 100% of the area of a side region may be encompassed within the adjacent sense electrodes, excepting the area of gaps 104 a. In various embodiments, some or all sense electrodes in sense electrode layer 45 may be interpolated with one or more adjacent sense electrodes. In certain embodiments, touch sensor 10 may include any number of sense electrodes suitable for its shape and size.

FIG. 4C illustrates a pattern created by overlaying drive electrode layer 40 with sense electrode layer 45 that could be used in touch sensor 10 in FIG. 1. Overlaying drive electrodes 102 f, 102 g, 102 h, and 102 i with sense electrodes 103 f, 103 g, 103 h, and 103 i creates one or more capacitive nodes, for example, capacitive nodes 140 e, 140 f, and 140 g.

Drive electrodes, as illustrated in FIG. 4A, generally run in one direction and are coupled to surface 101 a of substrate 101 described in conjunction with FIGS. 1 and 2. Sense electrodes, as illustrated in FIG. 4B, generally run in a direction orthogonal to the drive electrodes and are coupled to side 101 b of substrate 101 as described in conjunction with FIGS. 1 and 2. In various embodiments, the drive and sense electrodes can be aligned based on the different shape elements 420 and 421. In the embodiment illustrated in FIG. 4C, drive electrodes and sense electrodes are arranged such that respective side edges 416 and 418 of drive electrodes 102 f, 102 g, 102 h and 102 i are aligned with the ends of shape elements 421 of sense electrodes 103 f, 103 g, 103 h, and 103 i, and respective side edges 417 and 419 of sense electrodes 103 f, 103 g, 103 h, and 103 i are aligned with the ends of shape elements 420 of drive electrodes 102 f, 102 g, 102 h, and 102 i. Although drive electrodes and sense electrodes do not make electrical contact, they are able to capacitively couple to form capacitive nodes at the points where a drive electrode intersects or overlays a sense electrode.

Capacitive node 140 e is created when drive electrode 102 i is overlaid with sense electrode 103 h. Capacitive node 140 e is shaded a light grey and has an area of approximately 16 units, where each unit has an area of width W12 by width W16. Because capacitive node 140 e is located near the right hand edge of touch sensor 10, it may be referred to as an edge node in various embodiments. In certain embodiments, along its edges, touch sensor 10 may have any number of edge nodes suitable for its shape and size.

Capacitive node 140 f is created when drive electrode 102 i is overlaid with sense electrode 103 i. Capacitive node 140 b is shaded a darker grey and has an area of approximately 16 units, where each unit has an area of width W12 by width W16. Because capacitive node 140 f is located near the bottom, right corner of touch sensor 10, it may be referred to as a corner node in various embodiments. In embodiments where touch sensor 10 has a generally rectangular shape, touch sensor 10 will have four corner nodes. In certain embodiments, touch sensor 10 may have any number of corner nodes suitable for its shape and size.

Capacitive node 140 g is created when drive electrode 102 h is overlaid with sense electrode 103 h. Capacitive node 140 g is shaded darkest grey and has an area of approximately 16 units, where each unit has an area of width W12 by width W16. Because capacitive node 140 g is located away from edges and corners of touch sensor 10, it may be referred to as a center node in various embodiments. In various embodiments, nodes in touch sensor 10 located away from edges and corners will each be center nodes. In certain embodiments, touch sensor 10 may have any number of center nodes suitable for its shape and size.

With each node having an area of 16 units, capacitive nodes 140 e, 140 f, and 140 g each have approximately equal areas. In various embodiments, drive and sense electrodes may be configured such that capacitive nodes 140 e, 140 f, and 140 g each have approximately equal unit areas, which measure greater or fewer than 16 units. In certain embodiments, nodes with approximately equal areas may include nodes that each have a unit area that varies from each other node between 0% and 10%, and in particular, between 1% and 5%. In various embodiments, nodes with approximately equal areas may include nodes that each have a unit area that varies from each other node by up to 10%. In particular embodiments, nodes with approximately equal areas may include nodes that each have a unit area that varies from each other node by up to 1%. Creating a pattern that allows for equal areas for each node type, including edge, corner, and center nodes, requires a different cut in the conductive mesh than is required in the conventional approach discussed in conjunction with FIGS. 3A and 3B. For example, within touch screen 10 of FIG. 1, the conductive mesh is cut in FIGS. 4A and 4B such that there are two additional rectangular arms 424 illustrated for drive electrode 102 h and sense electrode 103 h than rectangular arms 324 illustrated for drive electrode 102 c and sense electrode 102 c in FIGS. 3A and 3B. Additionally, the cut in FIGS. 4A and 4B allows for wider center region 410 for drive electrode 102 i in comparison to drive electrodes 102 g and 102 h and wider center region 410 for sense electrode 103 i in comparison to sense electrode 103 g and 103 h. In various embodiments, drive and sense electrodes 102 and 103 may be any suitable size and comprise any suitable pattern than allows for edge nodes, corner nodes, and center nodes of approximately equal areas. In certain embodiments, cuts in the lines of conductive material comprising drive electrodes 102 may be similar to cuts in the lines of conductive material comprising sense electrodes 103. In particular embodiments, there may be variation in the size and shape of the rectangular arms or digits of drive electrodes 102 and/or sense electrodes 103 so long as the pattern created when drive electrodes 102 are overlaid with sense electrodes 103 creates edge nodes, corner nodes, and center nodes of approximately equal areas.

Technical advantages associated with edge nodes, corner nodes, and center nodes of approximately equal areas may include improved ability of touch screen controller 12 to address noise. Advantages may additionally or alternatively include an improvement in the uniformity of sensitivity across touch sensor 10. Further advantages may additionally or alternatively include increased signal size from edge and corner nodes.

Although this disclosure illustrates several configurations of touch sensor 10, these illustrations are not necessarily drawn to scale. Certain features have been exaggerated or enlarged for descriptive purposes. For example, in particular illustrations, the drive and sense electrodes may be enlarged in comparison to other components of touch screen 10 or in comparison to touch screen 10 itself.

Herein, “or” is inclusive and not exclusive, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A or B” means “A, B, or both,” unless expressly indicated otherwise or indicated otherwise by context. Moreover, “and” is both joint and several, unless expressly indicated otherwise or indicated otherwise by context. Therefore, herein, “A and B” means “A and B, jointly or severally,” unless expressly indicated otherwise or indicated otherwise by context.

This disclosure encompasses all changes, substitutions, variations, alterations, and modifications to the example embodiments herein that a person having ordinary skill in the art would comprehend. Moreover, reference in the appended claims to an apparatus or system or a component of an apparatus or system being adapted to, arranged to, capable of, configured to, enabled to, operable to, or operative to perform a particular function encompasses that apparatus, system, component, whether or not it or that particular function is activated, turned on, or unlocked, as long as that apparatus, system, or component is so adapted, arranged, capable, configured, enabled, operable, or operative. 

1. A touch position-sensing panel comprising: a sensing area comprising: a substrate; a plurality of first electrodes in a first layer, the plurality of first electrodes comprising conductive mesh and arranged in a first direction, the first layer having a first plurality of gaps formed therein; a plurality of second electrodes in a second layer, the plurality of second electrodes comprising conductive mesh and arranged in a second direction generally perpendicular to the first direction, the second layer having a second plurality of gaps formed therein; and a plurality of capacitive nodes formed by the capacitive coupling of the plurality of first electrodes in the first layer and the plurality of second electrodes in the second layer, each capacitive node formed at a location where an electrode of the plurality of first electrodes overlays an electrode of the plurality of second electrodes, the plurality of capacitive nodes comprising at least one center node, at least one edge node, and at least one corner node, the at least one center node, at least one edge node, and at least one corner node each having an area that varies from each other node by 0% or 10% or between 0% and 10%; wherein: the at least one center node is located away from edges of the touch position-sensing panel; the at least one edge node is located near one edge of the touch position-sensing panel; and the at least one corner node is located near two edges of the touch position-sensing panel.
 2. The touch position-sensing panel of claim 1, wherein the plurality of first electrodes in the first layer are on a first side of the substrate and the plurality of second electrodes in the second layer are on a second side of the substrate.
 3. The touch position-sensing panel of claim 1, wherein at least one electrode of the plurality of first electrodes and at least one electrode of the plurality of second electrodes each have an outer boundary comprising a repeating pattern.
 4. The touch position-sensing panel of claim 3, wherein the repeating pattern creates a first plurality of digits coupled to the at least one electrode of the plurality of first electrodes and a second plurality of digits coupled to the at least one electrode of the plurality of second electrodes.
 5. The touch position-sensing panel of claim 1, wherein: at least one electrode of the plurality of first electrodes comprises a first plurality of digits, the first plurality of digits on one side of the at least one electrode and each of the first digits being separated from another one of the first digits by a space of a plurality of first spaces; an adjacent electrode of the plurality of first electrodes comprises a second plurality of digits, the second plurality of digits on one side of the adjacent electrode and each of the second digits being separated from another one of the second digits by a space of a plurality of second spaces; and wherein the first plurality of digits and second plurality of digits are interpolated, such that a portion of each of the plurality of second spaces are occupied by a portion of the first plurality of digits and a portion of each of the plurality of first spaces are occupied by a portion of the second plurality of digits.
 6. The touch position-sensing panel of claim 5, wherein the area of at least one digit of the plurality of first digits is approximately equal to the area of at least one digit of the plurality of second digits.
 7. The touch position-sensing panel of claim 1, wherein at least one electrode of the plurality of first electrodes comprises a plurality of digits with a first portion and a second portion, the first portion of the plurality of digits located on a first side of the at least one electrode and the second portion of the plurality of digits located on a second side of the at least one electrode, such that each digit in the first portion shares a row with a digit in the second portion.
 8. The touch position-sensing panel of claim 1, wherein: at least one electrode of the plurality of first electrodes comprises a first plurality of digits with a first portion and a second portion, the first portion of the first plurality of digits located on one side of the at least one electrode and the second portion of the first plurality of digits located on an opposing side of the at least one electrode of the plurality of electrodes; and at least one electrode of the plurality of second electrodes comprises a second plurality of digits with a first portion and a second portion, the first portion of the second plurality of digits is located on one side of the at least one electrode and the second portion of the second plurality of digits located on an opposing side of the at least one electrode of the plurality of electrodes.
 9. The touch position-sensing panel of claim 1, wherein: the plurality of first electrodes in the first layer has a first plurality of gaps formed therein, a gap of the first plurality of gaps separating a first electrode of the plurality of first electrode from an adjacent electrode of the plurality of first electrodes; and the plurality of second electrodes in the second layer has a second plurality of gaps formed therein, a gap of the second plurality of gaps separating a first electrode of the plurality of second electrodes from an adjacent electrode of the plurality of second electrodes.
 10. The touch position-sensing panel of claim 1, wherein the at least one center node, the at least one edge node, and the at least one corner node each have an area that varies from each other node between 1% and 5%.
 11. A touch position-sensing panel comprising: a sensing area comprising: a substrate; a plurality of first electrodes in a first layer, the plurality of first electrodes formed of conductive mesh and arranged in a first direction; a plurality of second electrodes in a second layer, the plurality of second electrodes formed of conductive mesh and arranged in a second direction; wherein the plurality of first electrodes and the plurality of second electrodes overlap to create a node of a first type, a node of a second type, and a node of a third type, the node of the first type, the node of the second type, and the node of the third type each formed at a location where an electrode of the plurality of first electrodes overlays an electrode of the plurality of second electrodes; and wherein an area of the node of the first type, an area of the node of the second type, and an area of the node of the third type each varies from each other node by 0% or 10% or between 0% and 10%.
 12. The touch position-sensing panel of claim 11, wherein the plurality of first electrodes in the first layer are on a first side of the substrate and the plurality of second electrodes in the second layer are on a second side of the substrate.
 13. The touch position-sensing panel of claim 11, wherein the first direction is generally perpendicular to the second direction.
 14. The touch position-sensing panel of claim 11, wherein at least one electrode of the plurality of first electrodes and at least one electrode of the plurality of second electrodes each have an outer boundary comprising a repeating pattern.
 15. The touch position-sensing panel of claim 14, wherein the repeating pattern creates a first plurality of digits coupled to the at least one electrode of the plurality of first electrodes and a second plurality of digits coupled to the at least one electrode of the plurality of second electrodes.
 16. The touch position-sensing panel of claim 11, wherein at least one electrode of the plurality of first electrodes comprises a plurality of digits with a first portion and a second portion, the first portion of the plurality of digits located on a first side of the at least one electrode and the second portion of the plurality of digits located on a second side of the at least one electrode, such that each digit in the first portion shares a row with a digit in the second portion.
 17. The touch position-sensing panel of claim 11, wherein: at least one electrode of the plurality of first electrodes comprises a first plurality of digits, the first plurality of digits on one side of the at least one electrode and each of the first digits being separated from another one of the first digits by a first space; an adjacent electrode of the plurality of first electrodes comprises a second plurality of digits, the second plurality of digits on one side of the adjacent electrode and each of the second digits being separated from another one of the second digits by a second space; and wherein the first plurality of digits and second plurality of digits are interpolated, such that a portion of each of the second spaces are occupied by a portion of the first plurality of digits and a portion of each of the first spaces are occupied by a portion of the second plurality of digits.
 18. The touch position-sensing panel of claim 17, wherein the area of at least one digit of the plurality of first digits is approximately equal to the area of at least one digit of the plurality of second digits.
 19. The touch position-sensing panel of claim 11, wherein: at least one electrode of the plurality of first electrodes comprises a first plurality of digits with a first portion and a second portion, the first portion of the first plurality of digits located on one side of the at least one electrode and the second portion of the first plurality of digits located on an opposing side of the at least one electrode of the plurality of electrodes; and at least one electrode of the plurality of second electrodes comprises a second plurality of digits with a first portion and a second portion, the first portion of the second plurality of digits is located on one side of the at least one electrode and the second portion of the second plurality of digits located on an opposing side of the at least one electrode of the plurality of electrodes.
 20. The touch position-sensing panel of claim 11, wherein: the plurality of first electrodes in the first layer has a first plurality of gaps formed therein, a gap of the first plurality of gaps separating a first electrode of the plurality of first electrode from an adjacent electrode of the plurality of first electrodes; and the plurality of second electrodes in the second layer has a second plurality of gaps formed therein, a gap of the second plurality of gaps separating a first electrode of the plurality of second electrodes from an adjacent electrode of the plurality of second electrodes.
 21. The touch position-sensing panel of claim 11, wherein the node of the first type comprises a center node located away from edges of the touch position-sensing panel, the node of the second type comprises an edge node located near one edge of the touch position-sensing panel, and the node of the third type comprises a corner node located near two edges of the touch position-sensing panel.
 22. The touch position-sensing panel of claim 11, wherein the area of the node of the first type, the area of the node of the second type, and the area of the node of the third type each varies from each other node between 1% and 5%. 